This invention relates to bar code labeling systems, and in particular to a bar code labeling system that prints and applies a bar code label to articles being conveyed on a conveyer belt. More specifically, the invention detects the location of pre-printed bar code labels on an assortment of articles being transported on a conveyer belt in single file, and prints and applies another label to the article covering the pre-printed bar code label.
In large distributions applications, sortation conveying systems are typically used to fulfill orders of intermingled articles such as assortments of books, video cassette containers, packaged software, compact disc containers, etc. Workers load items into the system and the articles are conveyed in single file within individual pockets on a core conveyer belt for the sortation conveying system. As the assorted articles begin to move through the system on the core conveyer belt, the system reads pre-printed bar code information on each respective article. This bar code information is transmitted to a system controller that instructs the system with respect to further downstream processing and sorting of the articles into the various outgoing orders.
It is typical for a conveyer sortation system to include label printing and application stations along the core conveyer belt upstream of the stacking stations for the outgoing orders. Typically, the post-applied label is custom generated for the specific article after the pre-printed bar code on the article is read. The post-applied label sometimes contains another bar code specific to the company operating the sortation conveying system for use at check out, and also often contains tracking or other information pertinent to the product. In many cases, the post-applied bar code label is affixed to the article in a location different from the location of the pre-printed bar code on the article. This presents a situation in which two bar codes are present on the article, one of which is pre-printed and the other of which is post-applied. The presence of two bar codes on an article can, however, lead to confusion for check-out workers, and can also lead to improper tracking and inventory data monitoring. In some circumstances, it is therefore desirable for the post-applied label to cover the pre-printed bar code on the article.
The invention is an automatic overlabeling system that dynamically senses the location of a pre-printed bar code on an article, and custom prints and applies another label on the article covering the pre-printed bar code. Normally, xe2x80x9cbar codexe2x80x9d will be printed on the applied label. In this manner, only a single bar code is present on the article, and thus confusion by retail check-out workers or other workers using bar code scanners is alleviated.
The system dynamically determines the location of the pre-printed bar code on each respective article being moved along the core conveyer for a sortation conveying system. This is accomplished at a rate of approximately 250 articles per minute. The system includes a bar code scanning system which normally consists of a plurality of bar code scanners, each assigned to read along an assigned orientation in an assigned region above the conveyer in search of pre-printed bar code information on articles being moved along the conveyer. A typical system would have five such bar code scanners. Two linear scanners are used to read ladder orientated bar code. Three raster scanners are used to read picket fence orientated bar code. The system also includes a series of label printing and application stations, preferably six. Each is adjusted to apply labels at a specific elevation on the surface of articles being moved along the conveyer. The label printing and application stations are located downstream from the bar code scanners. Each label printing and application station preferably includes a photoelectric sensor that senses the presence of article being conveyed into the station, as well as a microprocessor or station controller. The system also includes an overall system controller, preferably a PC, which controls the bar code scanners, creates a label format data for the label printing and application stations, and determines which station is to be used to print and apply the label on the respective article. The system also preferably includes a photoelectric sensor located at the input of the system to detect a presence of articles entering the system, as well as an encoder that monitors movement of the conveyer to provide article position tracking data. The system controller inputs a signal from the system photoelectric sensor as well as data signals from the bar code scanners and outputs control signals to the micro-controllers for the various label printing and application stations. Based on the information gathered by the system photoelectric sensor and the bar code scanners, the system controller calculates the vertical and horizontal position at which the label should be applied on the respective article. This information is transmitted to the label printing and application stations. In turn, the appropriate label printing and application station applies a label to the surface of the article at a location that covers at least a portion of the surface on which the pre-printed bar code is located.
The system preferably operates in the following manner. Articles are moved along the conveyer in single file. As an article enters the system, it is sensed by the photoelectric sensor and tracked by the system controller using data from the conveyer encoder. The data from the encoder is also transmitted to the controllers for the various label printing and application stations. The system controller tracks all the articles passing through the system individually. When the system photoelectric sensor senses that an article is entering the system, the system controller instructs the bar code scanners to read the moving article. The bar code scanners transmit the following information to the system controller: 1) any decoded bar code data that has been read, 2) data on the position of the bar code label on the article, and 3) data on the length of the article. The system controller is pre-programmed with the mounting location of each bar code scanner. Based on this information, the system controller is programmed to select the appropriate label printing and application station for printing and applying the label to the article. As mentioned, each label printing and application station is adjusted to apply labels at a specific height on the surface of articles being moved along the conveyor. The system controller then transmits control signals to the appropriate label printing and application station, regarding both the required label format data and position information. As mentioned, each label printing and application station has a dedicated station controller (e.g. microprocessor) which receives the control signals from the system controller. The station controller processes the data sent by the system controller and calculates the correct horizontal (i.e., machine direction) label position location on the article. If the dynamically determined new label location is such that part of the new label would over hang or otherwise not be fully attached to the article surface, the station controller automatically adjusts the new label location data to ensure that the label is placed entirely on the article. When an article is detected by a photoelectric sensor for the appropriate label printing and application station, the station controller determines whether it has been instructed to label the article. If the station was not instructed to label the article, the article passes without being labeled to subsequent label printing and application stations. If the station was instructed to label the article, the station controller instructs the station to apply the printed label when the article is in the correct horizontal position relative to the label printing and application unit.
In the preferred system, there are six label printing and application units. Three of the label application and printing units are adjusted to apply labels to the surface of article being moved along the conveyer at a first defined elevation above the conveyer, normally the lowermost region. Two of the label printing and application units are adjusted to apply labels at a second defined elevation above the conveyer, which is positioned higher than the first defined elevation. One of the label printing and application units is adjusted to apply labels on the surface of articles being moved along the conveyer at a third defined elevation. The third elevation is higher than the second and first defined elevations. This configuration is preferred because it is more likely that pre-printed bar code information appears on the surface of articles at the lower elevations, whereas less are located at the middle or higher elevations. In addition, some articles being conveyed through the system may not even have sufficient height to extend upward into the adjusted position for the highest label printing and application unit.
The above-described process is repeated for all articles entering into the system. The system is designed to be able to accommodate multiple articles each having assorted dimensions being conveyed through the system in single file. Preferably, a system in accordance with the invention can process information relating to multiple articles concurrently such that as one or more articles are being labeled, other articles may have entered the system and be in various stages of tracking and calculating information for the respective article.